1. Field of the Invention
This invention relates generally to rapidly solidified copper-rich metal alloys which include certain specific amounts of boron. This invention also relates to the preparation of these materials in the form of rapidly solidified powder and consolidation of these powders (or alternatively the rapidly solidified ribbonlike material) into bulk parts which are suitably heat treated to have certain desirable properties.
2. Description of the Prior Art
Rapid solidification processing (RSP) techniques offer outstanding prospects of new, cost effective engineering materials with superior properties. [See Proc. Int. Conf. on Rapid Solidification Porcessing; Reston, VA, 1980; Published by Claitors Publishing Division, Baton Rouge, LA]. Metallic glasses, microcrystalline alloys, supersaturated solid solutions, and ultrafine grained alloys with highly refined microstructures, in each case often having complete chemical homogeneity, are some of the products that can be made utilizing RSP [see Rapidly Quenched Metals, 3rd Int. Conf. Vol. 1 and 2, Cantor, Ed., The Metals Society, London, 1978.]
Several techniques are well established in the state of the art to economically fabricate rapidly solidified alloys (at cooling rates of .about.10.sup.5 .degree. to 10.sup.7 .degree. C./sec) as ribbons, filaments, wire, flakes or powders in large quantities. One well known example is melt spin chill casting, whereby the melt is spread as a thin layer on a conductive metallic substrate moving at high speed to form a rapidly solidified ribbon. [See Proc. Int. Conf. on Rapid Solidification Processing, Reston Va., Nov. 1977].
The current technological interest in materials produced by RSP, especially when followed by consolidation into bulk parts, may be traced in part to the problems associated with micro and macro segregation and undesirable massive grain boundary eutectic phases that occur in highly alloyed materials during conventional slow cooling processes i.e. ingot or mold casting. RSP removes macro-segregation altogether and significantly reduces spacing over which micro-segregation occurs, if it occurs at all. The design of alloys made by conventional slow cooling process is largely influenced by the corresponding equilibrium phase diagrams which indicate the existence and co-existence of the phases present in thermodynamic equilibrium. The advent of rapid quenching from the melt has enabled material scientists to stray further from the state of equilibrium and has greatly widened the range of new alloys with unique structures and properties available for technological applications.
Many copper alloys are specified for services where superior corrosion resistance, electrical conductivity, good bearing surface quality and fatigue characteristics are required. In addition, it has a pleasing color, is non-magnetic and is easily finished by plating or lacquering. These alloys also can be easily welded, brazed or soldered. [See source book on Materials Selection, Vol, II, American Society of Metals, Ohio, 1977, Section VII-195 and 207].
Copper base alloys containing 10 to 30 wt. % nickel which are commercially known as cupro-nickel are widely used in a variety of applications e.g. condensers, condenser plates, distiller tubing, heat exchangers, electrical springs, relays, etc. due to excellent hot and cold workability, good mechanical properties and excellent corrosion resistance.
There has been limited effort, as reported in the prior art involving use of rapid solidification processing techniques, to synthesise new and improved copper base alloys. A need therefore exists to develop new copper base alloys with unique chemical compositions and structures exhibiting superior mechanical properties, corrosion and/or oxidation resistance for numerous engineering applications.